[C++][Python] Keep and deprecate ARROW_PYTHON CMake option for backward compatibility

[asfimport]

ARROW-6858 removed ARROW_PYTHON CMake option because ARROW-16340 moved cpp/src/arrow/python/ to python/pyarrow/src/. But it broke backward compatibility. Users who use -DARROW_PYTHON=ON needs to -DARROW_CSV=ON, -DARROW_DATASET=ON and so on manually.

See also: #14224 (comment)

FWIW this broke my local development because of no longer including those (although I should probably start using presets ..)

Now, it's probably fine to remove this now Python C++ has moved, but we do assume that some C++ modules are built on the pyarrow side (eg we assume that CSV is always built, while with the above change you need to ensure manually that this is done in your cmake call).
In any case we should update the documentation at https://arrow.apache.org/docs/dev/developers/python.html#build-and-test to indicate that there are a few components required to be able to build pyarrow.

Eventually, we can remove ARROW_PYTHON CMake option but we should provide a deprecation period before we remove ARROW_PYTHON.

We should also mention that ARROW_PYTHON is deprecated in our documentation ( https://arrow.apache.org/docs/dev/developers/python.html#build-and-test ).

Reporter: Kouhei Sutou / @kou
Assignee: Kouhei Sutou / @kou

Related issues:

• [CI][Python] verify-rc python nightly builds fail due to missing some flags that were activated with ARROW_PYTHON=ON (is duplicated by)

PRs and other links:

• GitHub Pull Request #14273

_{Note: This issue was originally created as ARROW-17868. Please see the migration documentation for further details.}

[asfimport]

Kouhei Sutou / @kou:
Issue resolved by pull request 14273
#14273